Validation of a chiral capillary electrochromatographic method for metoprolol on a teicoplanin stationary phase

Abstract

A chiral capillary electrochromatographic (CEC) method for determination of the enantiomeric purity of either enantiomer of metoprolol has been validated. High resolution and efficiency separations (R s =2.5 and 80000 plates m−1, respectively) were achieved by use of a teicoplanin chiral stationary phase in the polar organic mode. Method validation showed that detection linearity, robustness, accuracy, and repeatability were adequate. The method was also shown to be sufficiently sensitive for the determination of a minor enantiomer; the limit of quantitation (LOQ) was determined to be 0.09% of the peak area of the enantiomer under investigation. A similar commercial column was subsequently evaluated by use of the validated method and found to yield results for metoprolol comparable with those obtained on the homepacked columns. Acceptable separations on this commercial column were also obtained for other β-blocking drugs; those for alprenolol were particularly noteworthy (R S =3.8 and 265000 plates m−1).